All right, let’s return for a moment to the question of Paul Dacre. Not so much how he misjudged the Miliband story, but what the fallout tells us about the situation at the Mail.

Fortuitously, a new edition of one of the best books ever written about journalism has just been published. No, I don’t mean Manufacturing Consent, which has its interesting points but is somewhat handicapped by Herman and Chomsky only having the very vaguest idea of how journalism actually works. (This is less worrying from two academics than the fact that there are people who make a living in journalism who follow their analysis and don’t appear to know how journalism works. Happily, most of those people are kept on the comment pages of the Guardian and New Statesman where they can’t do much harm.)

I am of course referring to the classic Stick It Up Your Punter! by Peter Chippindale and Chris Horrie, which tells the story of the Sun during its glory days of the 1970s and 1980s, and a gripping tale it is too. The only criticism I’d make of it is the one I always make of books about Fleet Street, namely that there are too many true stories left out on the grounds that readers would never believe them. But seriously, it’s quite wonderful, and if you’ve never read it, treat yourself.

This has some relevance because, to a very large extent, it tells the story of Kelvin MacKenzie’s editorship, and it’s hard to convey to people nowadays just how much Kelvin bestrode the landscape like a colossus. He had a very sharp sense of exactly what the punters wanted; whether you liked his editorial decisions or not, he was a superb technical editor putting out a highly professional product every day; and yes, that brash flamboyance, which was so much part of 1980s culture, really put the Sun into a position of being able to dictate the news agenda. It’s never quite regained that since; the agenda-setting mantle has long since passed to the Mail, though the Sun continues to outsell it.

One of the most interesting points to consider is how often Kelvin screwed up, and sometimes disastrously, Hillsborough of course being by far the worst blot on his record, but considering the sheer number of times he was caught out publishing dodgy stories or monstering blameless members of the public, for years he seemed to lead a charmed life. If circulation was high and the finances were healthy and the Currant Bun was beating the competition, Uncle Rupert was happy and Kelvin was untouchable. Until there came a time when he wasn’t untouchable any more, when he was being caused trouble by relatively minor things that he could have shrugged off a few years previously. The point being that every regime, no matter how solid it looks on the surface, will weaken eventually. If only because the boss has been there for so long people get sick of the sight of him.

It’s a common process in politics and in many other institutions. The weakening is often hard to spot in its earlier stages. It becomes obvious when there’s blood in the water. Think of the “Back to Basics” affair, and how John Major’s government was crippled by relatively minor sexual scandals while both his predecessor and successor survived much worse.

Are we now at that point with the Dacre regime at the Mail? Dacre is not Kelvin MacKenzie, and eschewing publicity has probably helped him last as long as he has, coupled with being extremely good at what he does. Circulation is still booming, and the Mail is one of the few papers that’s still profitable. But he’s been in post for over twenty years now, and nobody lasts forever. Bearing in mind that he’ll turn 65 next month, the unthinkable scenario of the Mail without Dacre becomes quite thinkable. And since the Mail, unlike some papers, doesn’t change editors at the drop of a hat – David English helmed the paper for 21 years before Dacre took over – one could hardly blame hacks for speculating.

So there are, I understand, alliances being formed and people are moving into position for the post-Dacre era. And indeed the great man has made some concessions lately – the axing of Melanie Phillips being one gesture towards smoothing out the paper’s sharper edges. As for the Miliband story, it won’t have escaped notice that, following that Mail on Sunday reporter gatecrashing Ed’s uncle’s memorial, MoS editor Geordie Greig was very quick to apologise in a way that invites comparison with his opposite number at the daily. It’s probably fair to say, too, that Greig and Dacre are not known for being the best of buddies.

But yes, I sense weakness in the air, as much in the tone of the defence as anything. While I’m none too fond of Mehdi Hasan, for instance, devoting two pages to attacking him – well, what’s the point? From the Mail’s point of view, Hasan should be a fly to be swatted away, not a serious enemy who deserves a serious response.

Think of the timeline around Hackgate two years ago. There was an entire process of Murdoch setting off controlled explosions, getting damaging information out in vast infodumps almost too big to process, getting rid of compromised personnel, eventually closing the most compromised newspaper, all aimed at limiting the damage to the company. The ruthlessness with which he went about it indicated that he wasn’t as vulnerable as he appeared. If the Mail is going off on goose chases against enemies that ultimately don’t matter… well, perhaps its veteran editor is more vulnerable than he appears.